Hannibal, one of the greatest military commanders in history, was born in 247 B.C.E., the son of Hamilcar Barca, the Carthaginian commander that made significant advances into Sicily during the same century. His younger brother Hasdrubal Barca (not to be confused with the Hasdrubal that was his brother-in-law) and he were set in charge of Spain by their father. Hannibal and Hasdrubal Barca conquered several Spanish cities, and by late in the century they were poised to build a formidable empire.

Hannibal's project to cross the Alps began in 218 B.C.E., and he did not reach Rome until 211 B.C.E. The historian Livy, writing in the first century, vividly describes the impression that the Alps must have made on Hannibal and his troops: "The dreadful vision was now before their eyes: the towering peaks, the snow-clad pinnacles soaring to...